1. Field of the Invention
The present invention generally relates to a detecting arrangement and more particularly, to an attitude or posture detecting arrangement for objects, for example, electronic parts or the like, which is capable of positively detecting at high speeds, whether or not the object held by a holding device such as a suction nozzle, etc. is correctly supported or whether or not the object is a correct object as required, with a high detecting reliability.
2. Description of the Related Art
A one example of conventional object attitude detecting arrangements, a part attitude detecting arrangement for a chip type electronic part mounting machine will be described hereinbelow with reference to FIG. 2.
In FIG. 2, the chip-type electronic part 1 (referred to as a chip part hereinbelow) which is an object to be detected is fed from a part supply section 2, and is held, through vacuum attraction, by one of suction nozzles 4 of a mounting head 3 of the machine to be intermittently rotated. Subsequently, after being subjected to a positional adjustment in X and Y directions by an X-Y direction adjusting section 6, the chip part 1 is checked for its attracted attitude by a detector 7, and is transported up to a print circuit board 9 supported on an X-Y table 8 so as to be mounted thereon as required.
Referring also to FIGS. 3 and 4, the attitude detecting method adopted in the conventional detecting apparatus as described so far will be explained. FIG. 3 shows a state in which the chip part 1 is normally attracted onto the suction nozzle 4, while FIG. 4 shows a state in which the chip part 1 is abnormally attracted thereto.
As shown in FIGS. 3 and 4, a pair of light transmitting type photo-sensors 10 and another pair of light transmitting type photo-sensors 11 (referred to merely as photo-sensors hereinafter) are disposed vertically in two stages at opposite sides of the object 1 held by the suction nozzle 4 as illustrated. The pair of spaced photosensors 10 are disposed immediately below the suction nozzle 4 for detecting the presence or absence of the chip part 1, while the pair of spaced photo-sensors 11 are disposed in a position that is located under the lower end of the suction nozzle 4 by a distance greater than a thickness t of the chip part 1, but less than a long side L of said chip part 1. In the above-described case, if the photosensors 10 are in the "on" state, the chip part 1 is not present therebetween. Meanwhile, when the photo-sensors 10 are in the "off" state, with the photo-sensors 11 being turned "on", it is indicated that the chip part 1 is normally attracted as shown in FIG. 3. On the contrary, if both pairs of the photo-sensors 10 and 11 are in the "off" state, abnormal attraction of the chip part 1 is determined as illustrated in FIG. 4.
However, the conventional attitude detecting arrangement as described so far has a problem in that, even with respect to the chip part normally attracted onto the suction nozzle 4, if said chip part is incorrectly oriented in a horizontal plane by 90.degree. as is the chip part 1a shown by chain lines in FIGS. 5(a) and 5(b), despite a normal posture thereof in the direction of thickness thereof, it is impossible to effect a correct detection.